Facile construction of type-II Sn-doping BiOCl/WO₃ heterojunction with enhanced visible-light response and charge separation toward the application in photocatalysis

In order to effectively address the global environmental issue and energy crisis, developing a satisfying photocatalyst with high solar response and efficient carrier separation efficiency is promising and still challenging. In this study, a feasible and effective strategy from the perspective of multi-scale regulation that integrating element doping and heterostructure construction as well as morphology control is used to improve the degradation efficiency in antibiotic removal. A Sn4+ doped BiOCl (BOC-Sn) integrated Sn-doped WO3 (WO3-Sn) photocatalyst with propelling photocatalytic degradation for tetracycline (TC) was fabricated via one-pot thiourea-assisted hydrothermal method and as-obtained catalysts were denoted as (BOC-WO)-Sn-Tux (x is the molar amount of thiourea in the synthesis). By regulating the content of thiourea, the optimized (BOC-WO)-Sn-Tu1 photocatalyst exhibits ultrafine grain size, expanded visible-light response and fast carrier transport. Driven by visible light, the TC dissociation rate mediated by (BOC-WO)-Sn-Tu1 surpassed that of BOC-WOwith a photodegradation rate constant k-value 5.75 times higher than that of WO3-Sn. Analysis of energy band configuration in the BOC-Sn and WO3-Sn photocatalyst suggests that these modifications can effectively promote the photocarriertransport with type-II at the heterojunction interfaces and passivate trap sites that reside within the (BOC-WO)-Sn-Tu1 catalysts. Benefited from the stronger reduction potential, center dot O-2(-) with high yield acts as the crucial active species in the photocatalytic reaction system verified by the trapping experiments and electron paramagnetic resonance (EPR) spectra detection. This work opens a new route in designing an effective photocatalytic system by integrating element doping and heterostructure construction as well as morphology regulation for environmental remediation.